Present invention relates to a finish for synthetic filament yarn processed in friction-texturing, more precisely a finish applicable to various types of partially oriented yarn (POY), ranging from coarse-denier to fine-denier and from semi-dull to bright yarns, to be processed with a draw-texturing machine (DT machine) operated with a wide range of processing speed, wherein the specifically designed finish minimizes fluffs in yarn production, and fume and varnish buildup on heater surface and snow deposit in texturing process.
Recently, draw-texturing speed has been increased above 1000 m/min owing to the improved performances of DT machines, POY and finishes. And POY consisting of fine=denier monofilament, 1.0 denier or less, has been able to be produced. The improvement has urged a demand of three different finishes for fiber producers, i.e., finishes for conventional low-speed friction texturing (with contact heaters), finishes for high-speed friction texturing (with non-contact heaters) and finishes for fine denier yarn. Such demand results in complicated finish application control and there comes out a new requirement for unifying those various finishes into a single versatile finish.
For solving the problem, a finish containing a polyether produced by end-capping an ethylene-oxide-propylene-oxide adduct of polyether with alkyl groups forming ether bonds as a major component has been proposed in Japanese Patent Publication Sho-62-25789 for applying to filament yarn fed to high-speed processes. The finish containing the component enables to increase friction-texturing speed indeed, but it is not a versatile finish applicable to both filament yarn processed in high-speed friction-texturing and fine denier yarn because the above-mentioned polyether contains high ratio of propylene oxide and forms weak finish film that cannot prevent a lot of fluffs generated on fine denier yarn.
For applying to POY of fine denier monofilament to be processed in high-speed friction texturing, a finish formula containing 30 to 70% of a polyether having 1000 to 5000 molecular weight which was produced by end-capping an EO/PO adduct of a polyhydric alcohol with alkyl groups and 10 to 30% of a polyether having 7000 to 12000 molecular weight which was produced by adding EO and PO to a polyhydric alcohol, as major components, and also containing 2 to 10% of a polyether having 18000 to 28000 molecular weight which was produced by adding EO and PO to a polyhydric alcohol and 4 to 15% of branched-chain fatty acid ester having a viscosity of 2 to 5 cPs at 75° C. has been disclosed in Japanese Patent Publication Hei-7-6134.
The formula enables to texture fine denier yarn within wide range of processing speed from low to high indeed, but it is not possible to apply the formula to coarse denier yarn in addition to fine denier yarn because the formula imparts excessively low filament-to-filament static friction at normal temperature due to the high ratio of polyether having a molecular weight of 7000 or more and results in poor package buildup of coarse denier POY consisting of monofilament of 2.0 dtex or more. And the branched-chain fatty acid ester blended as a lubricant generates more stain on heater surface than polyethers or esters containing EO and PO though it generates less stain on heater surface than linear-chain fatty acid esters.
For applying to fine denier yarn processed in high-speed friction texturing, a finish formula containing 30 to 50% of a polyether having 1000 to 3000 molecular weight and 30 to 50% of a polyether having 5000 to 7000 molecular weight as major components and also containing 5 to 15% of an EO (1 to 5 moles) adduct of C6-18 alcohol being esterified with C6-18 fatty acid has been disclosed in Japanese Patent 3086153. The formula enables to texture fine denier yarn within wide range of processing speed from low to high, but it is not possible to apply the formula to coarse denier yarn in addition to fine denier yarn because the formula imparts excessively low filament-to-filament static friction at normal temperature due to the high ratio of polyether having 5000 to 7000 molecular weight and results in poor package buildup of coarse denier POY consisting of monofilament of 2.0 dtex or more. In addition, the compound used as a friction-decreasing agent, which was produced by esterifying an EO (1 to 5 moles) adduct of C6-18 alcohol with C6-18 fatty acid, has a low molecular weight and causes a fuming trouble in a process with DTY machines having low fume-exhausting performance.